The object of these links is allowing free rotation of the chain in order to prevent twisting and thus permitting the work when being properly tensioned.
As already known, such links are comprised by a female part, a male part and a nut. Rotary attachment is attained between the female and the male with their nut. Thus, the nut threaded onto the male portion is then released in order to prevent unthreading during working, with the resulting loss of the chaincable and anchor.
It is already known, in the manufacture and use of swivels for chaincables, that the engagement between the nut and the male rod is actually established by means of threads requiring an expensive and thorough machining process, one of the threads used being the "ACME American thread of reduced height".
In spite of the efficiency of this arrangement, its manufacturing has a high final cost due to its particular features; this has been one of the basic reasons of the research giving as a result the improvements object of the instant invention, resulting in a substantial reduction of the mentioned cost of the finished product. Further, such improvements are based on technical merits, duly proven in corresponding tests.
In order to illustrate the advantages of the instant invention, the same will be hereinbelow described in connection with a preferred embodiment which in no way is intended as a limitation of the scope of the invention.